Lew, the best advice I can give you for a definitive answer, is to recommend that you read:
' The Road to Russia : Arctic Convoys 1942' by Bernard Edwards
Published by Leo Cooper, Barnsley, 2002
ISBN 0 85052 898 4
Incidentally, the awful fate of Convoy PQ17 might have been averted by using another route, away from the threat of German surface units in the Norwegian fjords, but in truth the fault lay with our Admiralty, which ordered the RN escorts to abandon the convoy, and for the merchantmen to disperse. The main threat, the Tirpitz, never left her moorings, and the unescorted convoy was torn apart by U-Boat packs. The route was OK, but Admiralty thinking was timorous, to say the least.